Isolated Ni Atoms Enable Near-Unity CH Selectivity for Photothermal CO Hydrogenation.

Photothermal hydrogenation of carbon dioxide (CO) into value-added products is an ideal solution for addressing the energy crisis and mitigating CO emissions. However, achieving high product selectivity remains challenging due to the simultaneous occurrence of numerous competing intermediate reactions during CO hydrogenation. We present a novel approach featuring isolated single-atom nickel (Ni) anchored onto indium oxide (InO) nanocrystals, serving as an effective photothermal catalyst for CO hydrogenation into methane (CH) with a remarkable near-unity (∼99%) selectivity. Experiments and theoretical simulations have confirmed that isolated Ni sites on the InO surface can effectively stabilize the intermediate products of the CO hydrogenation reaction and reduce the transition state energy barrier, thereby changing the reaction path to achieve ultrahigh selective methanation. This study provides comprehensive insights into the design of single-atom catalysts for the highly selective photothermal catalytic hydrogenation of CO to methane.